          url "http://localhost:9200"}}]
   {:index-name index-name
    :ids-inst (atom nil)
+   :cache-inst cache-inst
    :default-set-type (atom set-type)
    :population-use (atom population-use)
    :instance-context (es/create-context

        call [[divide-by-preset]] for the first invocation of [[instances-load]]

  * **:url** the URL to the DB (defaults to `http://localhost:9200`)
  * **mapping-type** map type name (see ES docs)

Example
-------

  `(let [conn# (connection)
         ~'index-name (:index-name conn#)
         ~'ids-inst (:ids-inst conn#)
         ~'cache-inst (:cache-inst conn#)
         ~'instance-context (:instance-context conn#)
         ~'stats-context (:stats-context conn#)
         ~'population-use (:population-use conn#)
